This is the first application filed for the present invention.
Not Applicable.
This invention relates to tubing coupling devices and, more particularly, to a tubing connector for expediting coupling of a tubing used in pressurized fluid systems.
In the plumbing industry, tubing made from polymer or composites is gaining acceptance and the applications for such tubing have been developing rapidly. Synthetic tubings are made from cross-linked polyethylene, for example, and are used for water distribution systems. Composite tubing is a multi-layer tubing which generally consists of an inner layer of a plastic material, an intermediate layer of aluminium alloy and an outer layer of a plastic material. Composite tubing provides the advantages of both metal and plastics and is used for a wide range of applications because of its flexibility and strength, especially its resistance to rupture when subject ed to relatively high temperature and pressure. Multi-purpose composite pressure tubing can be used both indoors and outdoors, cast in concrete, concealed in walls, floors and ceilings or surface mounted. It can be used for hot and cold water distribution, under surface floor heating, ice melt systems for sidewalks and driveways, air conditioning systems, compressed air and industrial process piping. Composite tubing is available, for example, from IPEX, which produces tubing (KITEC(copyright)) consisting of aluminium tubing laminated between two layers of polyethylene. To produce this tubing, an aluminium strip is formed, overlapped and then ultrasonically welded. Layers of a polyethylene are then applied with adhesive to form a bond with the aluminium tubing. The result is a tubing that does not rust, corrode or tuberculate. Couplings for synthetic and composite tubing are commercially available.
U.S. Pat. No. 6,095,571, entitled TUBING CONNECTOR which issued on Aug. 1, 2000, Applicant describes a tubing connector for use with synthetic and composite tubing. Elastic seal rings are supported in grooves in an external periphery of a connector portion of the tubing connector. Each of the grooves has a depth that approximates a thickness of the seal ring and a width greater than the width of the seal ring. When the connector portion is inserted in the tubing and radial pressure is exerted on the tubing by a crimp ring, the plastic in an inner periphery of the tubing intrudes into each annular groove and further compresses the seal ring inwardly in the groove. The remainder of the tubing overlapped by the crimp ring is compressed tightly around the external periphery of the connector portion.
In the prior art, crimp rings are a separate component of the tubing connector. Consequently, the crimp rings are sold separately and it is not always clear as to which crimp ring is suitable for a particular connector. Furthermore, when a tubing connector is being installed the crimp ring is first slid over the end of the tubing and then the tubing connector is inserted into an end of the tubing. While the tubing connector is inserted into the end of the tubing, the crimp ring, if not restrained, is able to move freely along the tubing. This may cause some inconvenience, particularly when a connector is applied to a long run of vertically oriented tubing. Besides having to hold the crimp ring while inserting the tubing, it is also necessary to hold the crimp ring while the crimping tool is positioned. If space is limited around the tubing, this may be difficult to do. In many situations it is also difficult to ensure that the crimp ring is in an optional location when it is crimped. This is generally due to the fact that visibility or access to the tubing is restricted by surrounding structure. If the crimp ring is not crimped at the optional location over the connector, the connection may break. There therefore exists a need for an improved tubing connector that facilitates installation.
In order to facilitate the insertion of a tubing connector into the end of a composite tubing, a reaming tool is usually used to enlarge and bevel the end of the tubing. Prior art reaming tools generally include an elongated shaft that carries cutters for bevelling an inside end of the tubing. Each cutter has a cutting edge oriented at a predetermined angle with respect to the central axis of the elongated shaft. The shaft has a diameter slightly greater than an internal diameter of the tubing. One end of the shaft is tapered for easy insertion into the end of the tubing, and the other end is usually attached to a handle. When the tapered end of the shaft is inserted into the tubing, a user applies torque and axial pressure to force the reaming tool into the tubing. When the cutters reach the end of the tubing, rotation of the shaft causes the cutting edges to bevel the inner end of the tubing. Applying the axial pressure simultaneously with rotating the tool makes the reaming work difficult, especially if the tubing is wet or slipping. Consequently, there also exists a need for an improved reaming tool.
It is therefore an object of the invention is to provide a tubing connector for a composite tubing that can be rapidly and accurately installed to provide a dependable fluid tight fitting.
Another object of the invention is to provide a tubing connector which has an integral crimp ring to facilitate the installation of the tubing connector.
Yet a further object of the invention is to provide a reaming tool for a composite tubing that is easy to use and reduces effort.
In accordance with one aspect of the invention, a tubing connector comprises a rigid tubular body having a fitting end, a cylindrical connector end, and a bore that extends from the fitting end to the connector end. A crimp ring is connected to the fitting end in a concentric relationship with the connector end to permit the tubing to be slid over the connector end under the crimp ring. The crimp ring is adapted to be compressed around the outer periphery of the end portion of the tubing. At least one opening extends radially through the crimp ring adjacent the fitting end to permit one end of the tubing to be seen in order to ensure that the tubing is completely inserted into an annulus between the connector end and the crimp ring. The crimp ring is made of a rigid deformable material, such as a copper alloy.
In accordance with a further aspect of the invention, there is provided a method of manufacturing a tubing connector for a tubing having a plastic inner periphery comprising steps of forming a shoulder on a fitting end of the tubing connector; sliding a crimp ring over a connector end of the tubing connector and onto the shoulder; and connecting-the crimp ring to the shoulder so that an annulus for receiving the tubing is formed between the connector end and the crimp ring.
In accordance with a further aspect of the invention there is provided a reaming tool for enlarging and bevelling an open end of a tubing to facilitate insertion of the tubing connector into the tubing. The reaming tool comprises a shaft and at least one cutter attached to the shaft. The cutter has a cutting edge oriented at a predetermined angle with respect to a longitudinal axis of the shaft. A guide screw is attached to a free end of the shaft, and has an external surface adapted to enlarge the open end of the tubing and automatically draw the cutting edge towards the open end of the tubing when the shaft is rotated in one direction.
The guide screw is preferably a cylindrical body having a plurality of parallel spiral ridges on the external surface. The guide screw preferably has a diameter greater than a diameter of an internal diameter of the tubing so that the end of the tubing is slightly expanded as the guide screw enters the tubing.
The advantages of the tubing connector in accordance with the present invention relate to the integral crimp ring. With an integral crimp ring, shipping and handling are facilitated and there is no possibility of buying or using the wrong crimp ring for a given tubing connector. The integral crimp ring also facilitates installation of the tubing connector, especially when the tubing is not horizontally oriented, or space around the tubing is limited. The integral crimp ring also ensures that the crimp ring is optionally located over the connector end where it is crimped. A good fluid seal is thereby ensured.
The reaming tool in accordance with to the present invention advantageously reduces the labour associated with installation of the tubing connector because the user needs only to rotate the tool in order to enlarge and bevel the end of the tubing. Axial force is not required.
Other features and advantages of the present invention will be understood with reference to the description of the preferred embodiments which follows.